The present invention relates to an image capturing apparatus such as digital camera and video camera.
In an image capturing apparatus that converts into electric signal an image formed on an image capturing element such as CCD and that thereby records the image, in general, incident light from a subject is imaged on the image capturing element by an optical system composed of optical members, and an effective image formed on an effective part of the image capturing element is converted into electronic data and is then recorded. That is why both a number of pixels of the image capturing element and a number of effective pixels of the effective part are inscribed on commodity products.
For purpose of obtaining an enlarged image with a reduced angle of view in an image capturing apparatus, conventionally, there have publicly been known an optical zoom unit that moves at least one optical member of an optical system, thereby enlarges an image on the image capturing element, and records the enlarged image, and an electronic zoom unit that extracts part of an image on the image capturing element and records the enlarged image. There have been provided a large number of image capturing apparatus in which both the units are used.
For weakening so-called camera-shake that is shake of an image captured by an image capturing apparatus held by human hand, there have publicly been known a mechanical camera-shake correction unit that detects an amount of shake of the image capturing apparatus, moves part of an optical system and/or an image capturing element, and thereby carries out correction so as to prevent an image of a subject formed on the image capturing element from moving in course of image capture, and an electronic camera-shake correction unit that monitors change of image data with lapse of time and shifts an area where the image is extracted so as to reduce an amount of movement of the image of the subject in the extracted image.
In Japanese Patent Laid-Open Publication No. 2000-69351, No. H07-123317, and No. 2002-27312 are disclosed image capturing apparatus having both the mechanical camera-shake correction unit and the electronic camera-shake correction unit.
In Japanese Patent Laid-Open Publication No. 2000-69351 are disclosed an image capturing apparatus that performs correction with use of the electronic camera-shake correction unit when dynamic images are recorded and that performs correction with use of the mechanical camera-shake correction unit when still picture images are recorded, and an image capturing apparatus that uses only the electronic camera-shake correction unit when images are displayed on a monitor without being recorded and that uses the mechanical camera-shake correction unit and the electronic camera-shake correction unit in combination when images are recorded.
In Japanese Patent Laid-Open Publication No. H07-123317 is disclosed an image capturing apparatus that reduces power consumption by correction with use of the mechanical camera-shake correction unit when an angle of view is small and by correction with use of the electronic camera-shake correction unit when the angle of view is large.
In Japanese Patent Laid-Open Publication No. 2002-27312 is disclosed an image capturing apparatus that clearly captures consecutive images with use of the mechanical camera-shake correction unit and that corrects positional shift of an image of a subject between the consecutive images with use of the electronic camera-shake correction unit.
As disclosed in Japanese Patent Laid-Open Publication No. 07-123317, the mechanical camera-shake correction unit consumes large power and thus causes problems of decrease in maximum number of captured images or in maximum length of time of image capture, heat generation and the like. Capture of dynamic images particularly makes the problems enormous. In comparison with a large angle of view for image capture, furthermore, a small angle of view (with high magnification) necessitates larger movement of part of an optical system or an image capturing element and thus makes the problem more remarkable.
Though the electronic camera-shake correction unit does not cause the problems of power consumption, heat generation, and the like, on the other hand, it requires an image to be extracted partially from a captured image. Therefore, a problem occurs in that a resolution of the image effectively obtained is lowered in order to ensure a movable range of an area to be extracted. When a wide-angle image is to be captured, on the other hand, a problem occurs in that a maximum angle of view is limited to a small value in order to ensure a movable range of an area to be extracted.